1. Field of the Invention
The present invention relates to a fuel reforming apparatus, and more particularly, to a fuel reforming apparatus and a manufacturing method of the fuel reforming apparatus in which thermal energy is generated through an oxidation reaction of a fuel and a reformed gas containing hydrogen is generated through a reforming reaction of the fuel by using the thermal energy.
2. Description of the Related Art
A fuel cell is an electricity generating system for generating electrical energy by using a hydrocarbon fuel. Fuel cells can be classified into a polymer electrolyte membrane fuel cell and a direct oxidation membrane fuel cell, which is generally referred to as a direct methanol fuel cell (DMFC) in the art.
The polymer electrolyte membrane fuel cell has an excellent output characteristic, a low operation temperature, and fast starting and response characteristics in comparison to other types of fuel cells. In addition, the polymer electrolyte membrane fuel cell has an advantage that the fuel cell can be used in a wide range of applications such as a mobile power source for vehicles, a distributed power source for home or buildings, and a small size power source for electronic apparatuses.
The fuel cell system employing the polymer electrolyte membrane fuel cell includes a fuel cell main body that can be referred to as a stack, a fuel reforming apparatus which reforms a fuel to generate a reformed gas containing hydrogen and supplies the reformed gas to the stack, and an oxidant gas supply unit which supplies oxidant gas to the stack. The stack generates electricity through an electrochemical reaction of the reformed gas, which is supplied from the fuel reforming apparatus, and the oxidant gas, which is supplied from the oxidant gas supply unit.
In the fuel cell system employing the polymer electrolyte membrane fuel cell, the fuel reforming apparatus includes a thermal source unit which generates thermal energy through an oxidation reaction induced by an oxidation catalyst, and a reforming reaction unit which generates a reformed gas containing hydrogen by the use of the thermal energy and through a reforming reaction of the fuel.
For example, in a fuel reforming apparatus, a plurality of substrates made of stainless steel (SUS) are laminated so as to form a thermal source unit and a reforming reaction unit. The substrates are provided with a channel through which a fuel flows, a catalyst containing layer which is formed on a surface of the channel, and a catalyst layer which is formed on the catalyst containing layer to promote an oxidation reaction of the thermal source unit and a reforming reaction of the reforming reaction unit. The catalyst containing layer supports a catalyst layer, and is made of aluminum oxide (Al2O3) that can be formed over the surface of the channel.
In a fuel reforming apparatus, thermal energy is generated through an oxidation reaction of a gaseous fuel such as butane that can be easily obtained in the market. A reformed gas is generated through a reforming reaction of the gaseous fuel and by the use of the thermal energy.
In a fuel reforming apparatus that uses a gaseous fuel, a reforming reaction of the gaseous fuel occurs in the reforming reaction unit at a temperature in a range of 600° C. to 800° C. The thermal energy that is necessary to maintain the temperature is provided by a thermal source unit, which generates the thermal energy through an oxidation reaction of the gaseous fuel. The thermal source unit then supplies the thermal energy to the reforming reaction unit. In order to make the fuel reforming apparatus, a plurality of substrates having channels are laminated, and the laminated substrates bond at a high temperature (in a range of 500° C. to 900° C.).
However, the fuel reforming apparatus has a problem. The catalyst containing layer formed on the channels of the substrates is peeled off along with the catalyst layer or changes its phase during the bonding process at high temperature. Thus, durability of the catalyst containing layer deteriorates with time, which causes a shorter lifespan of the fuel reforming apparatus and degradation in the reliability of the fuel reforming apparatus.
Furthermore, the fuel reforming apparatus is manufactured by separately coating the channels with catalyst containing layer material such as aluminum oxide (Al2O3), which makes the manufacturing process of the fuel reforming apparatus more complicated. Accordingly, productivity of manufacturing the fuel reforming apparatus deteriorates.